The present disclosure relates to bearings, and, more particularly to gas bearings for aspirating seal assembly.
Rotary machines, such as gas turbines, are often used either for generating power with electric generators or for aircraft propulsion. At least some known rotary machines use aspirating seal assemblies to reduce leakage through a gap/clearance defined between stationary and rotating components of the gas turbine. Aspirating seal assemblies are non-contacting seals that typically operate with a tight clearance between the stationary and rotating components. Specifically, such aspirating seal assemblies include gas bearings to maintain the tight clearance between the rotating and stationary components. Gas bearings have a through-hole for injecting a pressurized gas against a rotating surface of the rotating component. The injection of pressurized gas may produce a film of the pressurized gas between the rotating surface and a stationary surface of the stationary component. Such a film generally functions as a load-bearing interface between the surfaces.
The load-bearing capacity of the gas bearings with the through-hole, decreases when there is a substantially large clearance between the surfaces. In such scenarios, the gas bearings may further include a counter bore or a recess disposed on the bearing surface and around the through-hole formed in the stationary component, and in gas communication with the through-hole to improve the load-bearing capacity of the gas bearings. Such counter bores may further create pressurized pockets around the surfaces to improve the load-bearing capacity of the gas bearings. However, during events such as rubbing of the surfaces against each other, the counter bore may get eroded. The erosion of the counter bores may reduce the load bearing capacity of the gas bearings and thereby affect stability and robustness of the gas bearings.
Accordingly, there is a need for an improved gas bearings and associated methods for improving a load bearing capacity of the gas bearings.